Conventionally, lesion information is obtained via surface visual analysis by the dermatologist. This limited information results in 20-30% of early melanomas going undetected. The estimated total direct cost associated with the treatment of melanoma in 2010 in the United States due to lack of early detection was $2.36 billion, with 65% of total cost going to continued care and another 20% of total cost going to the last year of life.
To see below the topmost layer of skin, a dermatoscope with a lighted magnifier may be used, but the image is limited to the top few layers of the surface of the skin. Additional imaging tools are available to the market, but none display or quantify the morphological disorganization characteristics as obtained from below the surface of the skin.
In the field of surgery and dermatology, lesion volume and location of disorganized tissue is critical in determining that the proper area is removed through biopsy for subsequent review by the pathologist. Current teaching techniques recommend utilizing a dermatoscope to select sampling location for biopsy. In a study by Dr. Hsu and Dr. Cockerell, 1123 histologically confirmed melanomas were reviewed and found significant diagnostic discrepancy between initial punch biopsies and re-excision specimens. While the excisional biopsy and sauceration shave biopsy demonstrated near 100% accuracy, punch technique was only 86.5% accurate. The paper reveals, “Due to the inherent intralesional heterogeneity of cutaneous melanoma, small punch biopsies may not always obtain representative specimens and may subject the patient to significant risk of misdiagnosis.”
Further misdiagnosis occurs among pathologists who either over diagnose or under diagnose a lesion. This is represented in a number of papers where discordance in dermatopathology among reviewers has been reported ranging from 14.3%-62.0%. As a result, typically only 2-5% of the total lesion is examined by the pathologist, and the remaining tissue sample is archived or discarded. This technique results in additional sections being ordered by the dermatologist if he or she believes the diagnosis is not correct, and perhaps the area of interest was not reviewed by the pathologist due to ineffective sectioning. Currently, no imaging device is known that offers the capability to guide sectioning as performed by a pathologist and his or her grossers, and this lack of image guidance in determining which areas of the lesion to section, in addition to subjective evaluation under the microscope, puts patients at undue risk.
For surgeons, ultrasound is the only medium for imaging a lesion below the skin in an attempt to view total volume. Unfortunately, ultrasound is unreliable on pigmented lesions and is difficult to read.
Recently, the MelaFind® Optical Imaging and Analysis Device has become available following FDA approval. It is a multispectral digital skin lesion analysis system used in the detection of melanoma among atypical skin lesions. The device uses light to image the skin through a layer of isopropyl alcohol to generate a classifier score result that provides information on the likelihood of a lesion being melanoma based on predefined image analysis algorithms. The device is used when a dermatologist chooses to obtain additional information on a decision to biopsy.
The MelaFind device currently utilizes multispectral images from 10 wavelengths of light, 430 nm to 950 nm, and produces colorless melanin absorption based images utilizing 10 spectral bands. These images however are not transformed into a 3-dimensional volumetric rendering of the lesion, and require interpretation by the user on the areas between each vertical layer image. The operation of some aspects of the MelaFind device are disclosed in U.S. Pat. Nos. 6,081,612 and 6,208,749, which are hereby incorporated by reference in this application in their entirety.